This invention relates to a stator for use in an electric machine which is excited by permanent magnets. More particularly, the invention relates to a stator having a bore hole into which arcuate permanent magnets are inserted, there being spring retaining elements inserted between the magnets which are fastened to the stator and rest against lateral edges of the magnets. The spring elements have spring arms which are connected together via a back part.
A stator of this general type is described in GB-PS 1 170 228, and has spring elements which are fastened to the stator by rivets. The spring arms of the spring elements rest against the lateral edges of the (shell-shaped) permanent arcuate magnets. The known stator is of two-pole design and therefore has two arcuate magnets which extend over a large circular arc. With this geometric configuration the magnets are held securely by the spring elements in spite of hard mechanical shocks, since the shocks only result, as a practical matter, in forces which act in the circumferential direction on the spring elements. The spring elements are secured against these forces by rivets.
In stator designs having more poles, for instance four or more poles, the permanent magnets extend over substantially smaller arcs, with the result that shocks stress the spring elements heavily in the radial direction.
It is an object of the present invention to design a stator for an electric machine excited by permanent magnets in such a way that secure fastening of the arcuate permanent magnets is insured in the event of hard shock stresses, while the spring elements are held securely at the stator without fasteners, the fasteners being capable of separate installation so as to simplify the assembly.